Segregation of tertiary base olefines



SEGRllGATION I OLE on'rEa'rIAnY BASE FINES PATENT oFF'lc William Engs and Richard Moravcc, Berkeley, Calif., assigncrs to Shell Developmentpom pany, San Francisco, Calif., a corporation of Delaware N0 Drawing. Application June 1, 1931,

g No. 541,526-

Serial 28 Claims. (01. 260-170 This invention relates to a process for the segregation of highly reactive olefines from olefinic mixtures containing more than three carbon atoms and ismore particularly concernedwith a continuous cyclic process which effects an economy in the necessary amount of selective solvent required to selectively absorb the highly reactive We have discovered that secondary alcohols can be prepared' simply and economically from olefine-containing gases of the type mentioned heretofore by practicing the selective removal of highly reactive olefines in a continuous manner wherein the selective absorbent is continuously recovered and recyc ed for further use.

The preferred mm 1 material is substantially stripped of hydrocar ons containing less than four carbonatoms and suitably fractionated into fractions containing hydrocarbons of the same number ofcarbon atoms. In certain instances,

it will be diflicult to remove traces of higher and lower carbon compounds, but their presence "is not detrimental to this process. In certain other situations, it may be desirable to operate with a fraction containing a mixture of carbon compounds such as a 4 and 5 carbon compound fraction. We prefer to practice our process with a substantially pure fraction of hydrocarbons of which each molecule contains the same number ofcarbon atoms. In segregating the hydrocarbons into suitable fractions, it will be found that it will be practically impossible to separate the parafiln hydrocarbons from the olefine hydrocarbons possessing the same number of carbon atoms without uneconomical and complicated procedure, As the' parafiin hydrocarbons may be considered as 'inert compounds in our process, their presence in their corresponding carbon compound fraction is not accompanied by any detrimental effect.

The fractions to be treated are thus characteristically composed of paraffin hydrocarbons, olefines, both iso-- "and normal, which yield secondary derivatives (hereinafter designated as secondary-base olefines), iso-olefines which yield phosphoric .acid are typical).

tertiary-base-olefines) and traces of diolefines such as butadiene and isoprene.

For illustrative purposes only, references will be had to a substantially pure 3-]?! fraction which represents a mixture of butane and butene obtained by distillation or condensation or both. Besides the butane there will benormally present isobutane, butene-l, butene-2 and isobutene. Isobutene is characteristic of the tentiary-base olefines as regards their high rates 10 of reactivity with various reagents. It is preferable to selectively remove the isobutene content prior to the conversion of the secondary-base olefines to secondary alcohols otherwise the ter- 7 tiary-base olefine polymerizes, causing localoverheating and thus decreasing the possible effective yields of secondary alcohols, or incom-' plete conversion of the secondary-base olefines results from the desire to avbid excessive polymerization of the tertiary-base olefine.

Selective absorbents for tertiary=base olefines are polybasic acids (of which sulfuric acid or In certain instances it may be desirable to employ monobasic acids as hydrochloric acid or organic acids as 25 benzene sulfonic acids or the sulfonic acids of the homologues of benzene.

The desired fraction," either in the gaseous or liquidstate--the liquid state promoting increased surface contact-is contacted with the 30 selective. absorbent in any suitable manner with or without pressure. For example, resort may ,be had to the agitation of the two agents in a common vesselor to counter-current flow. It is 1 desirablewhen employing a fraction in the gase- 35 ous state to conduct the process in counter-current fashion through a packed tower as this sys tem lends itself'most readily to intimate distribution of the tertiary-base olefine in the selective absorbent. Care must be taken that the 40 strengths of the selective absorbents are regu-' lated according to the temperature of the process and according to the character of the tertiary-base olefine. In practicing our invention, we preferably employ sulfuric acid containing 45 between and msol, preferably 65% H2804 as it apparently yields the best results with 4 or 5, carbon fractions and the like. While the 3-3 fraction is in intimate contact with the sulfuric acid the temperature is kept below 50 F. The isobutylene dissolves in this concentration of acid while the butene-l and 'butene-Z- substantially do not, but'remain associated with" thebutane. The sulfuric acid solution of isobutylene is mechanically separated from the un 55 dissolved fraction in any suitable manner as known to the art. The solution of-isobutylene is then heated to an elevated temperature around 180 F. which results in the formation of polymers of isobutylene which are hydrocarbonsimmiscible with sulfuric acid and therefore easily separated therefrom by any suitable operation known to the art. The polymers may be admixed with hydrocarbon fuel to' enhance the anti-knock rating of the latter. The recovered sulfuric acid is cooled to the desired. temperature prior to recycling in order to avoid solution of secondary-base olefines. The acid may be cooled prior to the separation of the polymer therefrom. Thus by continuously introducing a selective absorbent and a preferred hydrocarbon fraction ina'suitable contact vessel, selectively removing the tertiary-base olefine and continuously-recovering and recycling the selective absorbent, we have a closed, complete continuous process which furnishes a hydrocarbonfraction practically devoid of tertiary-base olefines, which yields a desirable anti-knock agent and which requires a minimum of selectiv absorbent to operate, all tending towards a flexible, easily regulatable process which constitutes an advance in the ,art relating to the preparation of secondary alcohols. I

When dioleflnes are present in the fraction undergoing treatment, they areselectively absorbed practically simultaneously "with the tertiarybase olefines and are removed with the solution of tertiary-base olefines. The selective absorbent which is recovered after separation of the polymers and recycled" to the absorption system is a dilute acid liquor which does not contain substantial amounts of alkyl sulfates.

While we have in the foregoing described in some detail the preferred embodiment of our invention and some variants thereof, it will be understood that this is only for the purpose of making the invention more clear and that the invention is not to be regarded as limited to the details of operation described, nor is it dependent upon the soundness or accuracy of the theories which we have advanced 'asto the reasons for the advantageous results attained. On the other hand, the invention isto be regarded as limited only by'the terms of the accompanying claims, in which it is our intention to claim all novelty inherent therein as broadly as is possible in view of the prior art.

We claim as ourinvention:

1. The continuous process for the selective re moval of tertiary-base olefines from hydrocarbon mixtures containing the same, comprising contacting the hydrocarbon mixture in the liquid phase with a selective acid absorbent for the tertiary-base olefine, separating .the solution of the tertiary-base oleflne from the undissolved hydrocarbon mixture, polymerizing the dissolved tertiary-base olefine, effecting the separation of the polymer from the selective absorbent and re- .cycling the recovered selective absorbent so that it is contacted with fresh hydrocarbon mixtures containing tertiary-base olefines.

2. The continuous process for the selective removal of tertiary-base olefines from hydrocar- .bonmixtures containing paraffin and olefine hydrocarbons of the same number of carbon atoms,

.comprising contacting the hydrocarbon mixture in' the liquid phase with a selective acid absorbent for the tertiary-base olefine, separating the. solution of the tertiary-base oleflne from theundissolved hydrocarbon mixture, polymerizing the dissolved tertiary-base olefine, effecting the separation of the polymer fromthe selective absorbentand recycling the recovered selective absorbent so that it is contacted with fresh hydrocarbon mixtures containing tertiary-base olefines.

3. The continuous process for the selective removal of tertiary-base olefines from a hydrocarbon mixture produced by cracking petroleum oil and containing paraffin and olefine hydrocarbons of the same number of carbon atoms, comprising contacting the hydrocarbon mixture in the liquid phase with a selective acid absorbent for the tertiary-basevolefine, separating the solution of the tertiary-base olefine from the undissolved hydrocarbon mixture, polymerizing the dissolved tertiary-base olefine, effecting the separation of the polymer from the selective absorbent and recycling the recovered selective absorbent, so that it is contacted with fresh hydrocarbon mixtures containing tertiary-base olefines.

4. The continuous process for the selective removal of tertiary-base olefines from a hydrocarbon mixture produced by cracking petroleum oil and which consists predominantly of paraffin and olefine hydrocarbons of the same number of carbon atoms, comprising contacting the hydrocarbon mixture in the liquid phase with a selective acid absorbent for the tertiary-base olefine, separating the solution of the tertiary-base olefine from the undissolved hydrocarbon mixture, polymerizing the dissolved tertiary-base olefine, effecting the separation of the polymer from the selective absorbent and recycling the recovered selective absorbent so that it is contacted with fresh hydrocarbon mixtures containing tertiarybase olefines.

5. The continuous process for the selective removal of isobutylene from a hydrocarbon mixture produced by cracking petroleum oil and which consists predominantly of paraffin and olefine hydrocarbons of four carbon atoms, comprising contacting the hydrocarbon mixture in the liquid phase with a selective acid absorbent for the isobutylene, separating the solution of isobutylene from the undissolved hydrocarbon mixture, polymeri'zing the dissolved isobutylene, effecting the separation of the polymer from the selective absorbent and recycling the recovered selective absorbent so that it is contacted with fresh hydrocarbon mixtures containing isobutylene.

6; Thecontinuous process for the selective removal of tertiary-base olefines from hydrocarbon mixtures containing the same, comprising contacting the hydrocarbon mixture with aqueous sulfuric acid between to 70% H2304 content, separating the solution of the tertiary-base olefine from the undissolved hydrocarbon mixture, polymerizing the dissolved tertiary-base olefine, ef-

fecting the separation of the polymer from the tiary-base olefine from the undissolved hydrocarbon mixture, polymerizing the dissolved tertiarybase olefine, effecting the separation of the polymer from the acid and recycling the recovered acid so that it is contacted with fresh hydrocarbon mixtures containing tertiary-basepleflnes.

sulfuric acid between 60 to 70% H2804 content,

separating the solution of tertiary-base olefine from the undissolved hydrocarbon mixture, polymerizing the dissolved tertiary-base olefine; ef-

fecting the separation of the polymer from the acid and recycling the recovered acid so that it is contacted withfresh hydrocarbon mixtures containing tertiary-base -olefines. fl k 9. The continuous process for the selective removal of tertiary-base olefines from a hydrocarbon mixture produced by cracking petroleum oil and which consists predominantly of paraflin and olefine hydrocarbons of the same number of carbon atoms, comprising contacting the hydrocarbon mixture with aqueous sulfuric acid between 60 to 70% H2804 content, separating the solution of the tertiary-base olefine from the undissolved hydrocarbon mixture, polymerizing the dissolyed tertiary-base olefine, effecting the separation of the polymer from the acid and recycling the recovered acid so that it is contacted with fresh hydrocarbon mixtures containing tertiary-base removal of isobutylene from a hydrocarbon mixture produced by cracking petroleum oil and which consists predominantly of paraffin and olefine hydrocarbons of four carbon atoms, comprising contacting the hydrocarbon mixture with aqueous sulfuric acid between 60 to 70% H2804 content, separating the solution of-isobutylene from the undissolved hydrocarbon mixture, polymerizing the dissolved isobutylene, effecting the separation of the polymer from the acid and recycling the recovered acid so that it is contacted ,with fresh hydrocarbon mixtures containing tertiary-base olefines. I 1

11. The continuous process for the selective removal of tertiary-base olefines fromhydrocarbon mixtures containing the same, comprising contacting the hydrocarbon mixture with aqueous sulfuric acid between 60 to,'70% H2804 content at a temperature below 90 F., separating the 9 solution of tertiary-base olefine from the undissolved hydrocarbon mixture, polymerizing the dissolved tertiary-base olefine, effecting the separation of the polymer from the acid and recycling the recovered acid'so that it is contac ted with fresh hydrocarbon mixtures containing tertiary base olefines.

a 12. The continuous process for the selective removal of tertiary-base olefines from hydrocarbon mixtures containingparaflih and olefine hy- 9 drocarbons of the same number of carbon atoms, comprising contacting the hydrocarbon mixture with aqueous sulfuric acid between to 70% HzSO4 content at a temperature below 90 F., separating the solution of tertiary-base olefine from the undissolved hydrocarbon mixture, polymerizing the dissolved tertiary-baseolefine, effecting the separation of the polymer from the acid and recycling the recovered acid sov that itis 10. The continuousprocess for the selective prising contacting the hydrocarbon mixture with aqueous sulfuric acid between 60 to H2804 content at a temperature below F., separating the solution of tertiary-base olefine from theundissolved hydrocarbon mixture, polymerizing the dissolved tertiary-base olefine effecting the sepcling the recovered acid so that it is contacted with fresh hydrocarbonmixtures containing tertiary-base olefines.

14. The continuous process for the selective removal of tertiary-base olefines from a hydrocarbon mixture produced by cracking petroleum oil and which consists predominantly of parafin and olefine hydrocarbons of the same number of carbon atoms, comprising contacting the hydrocarbon mixture with aqueous sulfuric acidbetween 60 to 70% H2804 content at a temperature below 90 g t; separating the solution of tertiarybase olefine from the undissolved hydrocarbon mixture, polymerizing the dissolved tertiary-base olefine,'effecting the separation of the polymer from the acid and recycling the recovered acid so that it is contacted with freshhydrocarbon mixtures containing. tertiary-base olefines:

i- 15. The continuous process for the selective removal of isobutylene from a hydrocarbon mixture produced by cracking petroleum oil and fine hydrocarbons of four carbon atoms, comprising contacting the hydrocarbon mixture with aqueous sulfuric acid between 60 to 70% H2804 content at a temperature below 90 F., separating thesolution of isobutylene from the undissolved hydrocarbon mixture, polymerizing the dissolved,

which consists predominantly of parafiin and oles aration of the polymer from the acid and recyundissolved hydrocarbon mixture, heating said solution to an elevated temperature sothatpolymervization of the dissolved tertiary-base olefine is effected, separating the polymer from the acid and recycling the recovered acid so that it iscon tacted with fresh hydrocarbon mixtures containing tertiary-base olefines.

17. The continuous process for the selective removal of tertiary-base, olefines from hydrocarbon mixtures containing paraffln and olefine hydrocarbons of the same number of carbonatoms,

comprising contacting the hydrocarbon mixture with aqueous sulfuric acid \between 60 to 70% 1 12804 content at atemperature below 90 It, separating the solution of the tertiary-base olefine from the undissolved hydrocarbon mixture, heating saidsolution to an elevated temperature so that polymerization of the dissolved tertiar'y base olefine i's effected, separating the polymer from the acid and recycling the recove ered acid so thatyit is contacted with fresh hydrocarbon mixtures containing tertiary-base olefines.

18. The continuous process for the selective removal of 'tertiary base olefines from'a hydrocarbon mixture produced by cracking petroleum oil and containing parafiin and olefine hydro,-

carbons of the same number of carbon atoms,

, comprising contacting the, hydrocarbon mixture with aqueous sulfuric acid between 60 to 70% H2804 content at a temperature below 90 F., separating the solution of tertiary-base olefine from the undissolved hydrocarbon mixture, heating said solution to an elevated temperature so that polymerization of the dissolved tertiarybase olefine is effected, separating the polymer from the acid and recycling the recovered acid so that it is contacted with fresh hydrocarbon mixtures containing tertiary-base olefines.

19. The continuous process for the selective removal of tertiary-base olefines from a hydrocarbon mixture produced by crackingpetroleum oil and which consists predominantly of paraflin and olefine hydrocarbons of the same number of carbon atoms, comprising contacting the hydrocarbon mixture with aqueous sulfuric acid between 60 to '70% H2804 content at a temperature below 90 F., separating the solution of tertiarybase olefines from the undissolved hydrocarbon mixture, heating said solution to an elevated temperature so that polymerization of the dissolved tertiary-base olefine is effected, separating the polymer from the acid and recycling the recovered acid so that it is contacted with fresh hydrocarbon mixtures containing tertiary-base olefines.

20. The continuous process for the selective removal of isobutylene from a hydrocarbon-mixture produced by cracking petroleum oil and which consists predominantly of paraffin and olefine hydrocarbons of four carbon atoms, comprising contacting the hydrocarbon mixture with aqueous sulfuric acid between 60lto 70% H2804 content at a temperature below 90 F., separating the solution of isobutylene from theundissolved hydrocarbon mixture, heating said solution to an elevated temperature so that polymerization of the dissolved isobutylene is effected, separating the polymer from the acid and recycling the recovered acid so that it is contacted with in the liquid phase with sulfuric acid of con-' centration below '70 per cent via absorption and subsequent heating whereby substantially only the tertiary olefine content forms polymers, separating from the acid liquor a substantial proportion of the resulting polymers and then bringing the separated acid liquor into contactwith an additional quantity of olefine mixture.

23. Process of producing hydrocarbons boiling within the gasoline range from a mixture of hydrocarbons containing normal and iso olefines derived from the pyrolysis of mineral oil, which comprises treating said mixture in the liquid phase with aqueous sulphuric acid, under conditions of acid concentration and temperature adapted to selectively form the absorption product of the tertiary iso olefines' present in said mixture with the formation of an acid liquor containing said absorption products, removing said acid liquor, heating the same, and separating the oily polymers thereby produced.

24. Process of producing hydrocarbons boiling within the gasoline range from a mixture of hydrocarbons containing normal and isoolefines derived from the cracking of mineral oil, which comprises treating said mixture with aqueous sulphuric acid of from 60 to 70% acid concentration while'maintaining a temperature at which there is selectively formed the absorption products of the tertiary isoolefines present in said mixture, thereby forming an acid liquor containing said absorption products, removing said acid liquor, heating the same, and separating the oily polymers thereby produced.

25. Process of producing hydrocarbons boiling within the gasoline range from a mixture of hydrocarbons containing normal and isoolefines derived from the cracking of petroleum oil, which comprises treating said mixture with aqueous sulphuric acid of from 60 to 70% acid concentration at a temperature of from to 25 C. thereby selectively forming the absorption products of the tertiary isoolefines present in said mixture with the formation of an acid liquor containing said absorption products, removing said acidliquor, heating the same, and separating the oily polymers thereby produced.

26. Process of producing hydrocarbons boiling within the gasoline range from a mixture of by drocarbons containing normal and isobutylene derived from the pyrolysis of mineral oil, which comprises treating said mixture in the liquid phase with aqueous sulphuric acid, under conditions of acid concentration and temperature adapted to selectively form the absorption product of the isobutylene present in said mixture with the formation of an acid liquor containing said absorption product, removing said acid liquor, heating the same, and separating the oily polymers thereby produced.

27. Process of producing hydrocarbons boiling within the gasoline range from a mixture of hydrocarbons containing normal and isobutylene derived from the pryrolysis of mineral oil, which comprises treating said mixture with aqueous sulphuric of from 60 to 70% acid concentration,

while maintaining a temperature at which there is selectively formed the absorption product of the isobutylene present in said mixture, thereby forming an acid liquor containing said absorption product, removing said acid liquor, heating the same, and separating the oily polymers thereby produced. I

28. Process of producing hydrocarbons boiling within the gasoline range from a mixture of hydrocarbons containing normal and isobutylene derived from the pyrolysisof mineral oil, which comprises treating said mixture with aqueous sulphuric acid of from 60 to 70% acid concentration at a temperature of from 0 to 25 0., thereby selectively forming the absorption product of the isobutylene present in said mixture with the formation of an acid liquor containing said absorption product, removing said acid liquor, heating the same, and separating the oily polymers thereby produced.

WILLIAM ENGS.

RICHARD MORAVEC. 

